/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.aop.support;

import java.io.Serializable;
import java.lang.reflect.Method;
import java.util.Arrays;

import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;

/**
 * Abstract base regular expression pointcut bean. JavaBean properties are:
 * <ul>
 * <li>pattern: regular expression for the fully-qualified method names to match.
 * The exact regexp syntax will depend on the subclass (e.g. Perl5 regular expressions)
 * <li>patterns: alternative property taking a String array of patterns.
 * The result will be the union of these patterns.
 * </ul>
 *
 * <p>Note: the regular expressions must be a match. For example,
 * {@code .*get.*} will match com.mycom.Foo.getBar().
 * {@code get.*} will not.
 *
 * <p>This base class is serializable. Subclasses should declare all fields transient;
 * the {@link #initPatternRepresentation} method will be invoked again on deserialization.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @author Rob Harrop
 * @see JdkRegexpMethodPointcut
 * @since 1.1
 */
@SuppressWarnings("serial")
public abstract class AbstractRegexpMethodPointcut extends StaticMethodMatcherPointcut
        implements Serializable {

    /**
     * Regular expressions to match.
     */
    private String[] patterns = new String[0];

    /**
     * Regular expressions <strong>not</strong> to match.
     */
    private String[] excludedPatterns = new String[0];


    /**
     * Convenience method when we have only a single pattern.
     * Use either this method or {@link #setPatterns}, not both.
     *
     * @see #setPatterns
     */
    public void setPattern(String pattern) {
        setPatterns(pattern);
    }

    /**
     * Set the regular expressions defining methods to match.
     * Matching will be the union of all these; if any match, the pointcut matches.
     *
     * @see #setPattern
     */
    public void setPatterns(String... patterns) {
        Assert.notEmpty(patterns, "'patterns' must not be empty");
        this.patterns = new String[patterns.length];
        for (int i = 0; i < patterns.length; i++) {
            this.patterns[i] = StringUtils.trimWhitespace(patterns[i]);
        }
        initPatternRepresentation(this.patterns);
    }

    /**
     * Return the regular expressions for method matching.
     */
    public String[] getPatterns() {
        return this.patterns;
    }

    /**
     * Convenience method when we have only a single exclusion pattern.
     * Use either this method or {@link #setExcludedPatterns}, not both.
     *
     * @see #setExcludedPatterns
     */
    public void setExcludedPattern(String excludedPattern) {
        setExcludedPatterns(excludedPattern);
    }

    /**
     * Set the regular expressions defining methods to match for exclusion.
     * Matching will be the union of all these; if any match, the pointcut matches.
     *
     * @see #setExcludedPattern
     */
    public void setExcludedPatterns(String... excludedPatterns) {
        Assert.notEmpty(excludedPatterns, "'excludedPatterns' must not be empty");
        this.excludedPatterns = new String[excludedPatterns.length];
        for (int i = 0; i < excludedPatterns.length; i++) {
            this.excludedPatterns[i] = StringUtils.trimWhitespace(excludedPatterns[i]);
        }
        initExcludedPatternRepresentation(this.excludedPatterns);
    }

    /**
     * Returns the regular expressions for exclusion matching.
     */
    public String[] getExcludedPatterns() {
        return this.excludedPatterns;
    }


    /**
     * Try to match the regular expression against the fully qualified name
     * of the target class as well as against the method's declaring class,
     * plus the name of the method.
     */
    @Override
    public boolean matches(Method method, Class<?> targetClass) {
        return (matchesPattern(ClassUtils.getQualifiedMethodName(method, targetClass)) ||
                (targetClass != method.getDeclaringClass() &&
                        matchesPattern(ClassUtils.getQualifiedMethodName(method, method.getDeclaringClass()))));
    }

    /**
     * Match the specified candidate against the configured patterns.
     *
     * @param signatureString "java.lang.Object.hashCode" style signature
     * @return whether the candidate matches at least one of the specified patterns
     */
    protected boolean matchesPattern(String signatureString) {
        for (int i = 0; i < this.patterns.length; i++) {
            boolean matched = matches(signatureString, i);
            if (matched) {
                for (int j = 0; j < this.excludedPatterns.length; j++) {
                    boolean excluded = matchesExclusion(signatureString, j);
                    if (excluded) {
                        return false;
                    }
                }
                return true;
            }
        }
        return false;
    }


    /**
     * Subclasses must implement this to initialize regexp pointcuts.
     * Can be invoked multiple times.
     * <p>This method will be invoked from the {@link #setPatterns} method,
     * and also on deserialization.
     *
     * @param patterns the patterns to initialize
     * @throws IllegalArgumentException in case of an invalid pattern
     */
    protected abstract void initPatternRepresentation(String[] patterns) throws IllegalArgumentException;

    /**
     * Subclasses must implement this to initialize regexp pointcuts.
     * Can be invoked multiple times.
     * <p>This method will be invoked from the {@link #setExcludedPatterns} method,
     * and also on deserialization.
     *
     * @param patterns the patterns to initialize
     * @throws IllegalArgumentException in case of an invalid pattern
     */
    protected abstract void initExcludedPatternRepresentation(String[] patterns) throws IllegalArgumentException;

    /**
     * Does the pattern at the given index match the given String?
     *
     * @param pattern      the {@code String} pattern to match
     * @param patternIndex index of pattern (starting from 0)
     * @return {@code true} if there is a match, {@code false} otherwise
     */
    protected abstract boolean matches(String pattern, int patternIndex);

    /**
     * Does the exclusion pattern at the given index match the given String?
     *
     * @param pattern      the {@code String} pattern to match
     * @param patternIndex index of pattern (starting from 0)
     * @return {@code true} if there is a match, {@code false} otherwise
     */
    protected abstract boolean matchesExclusion(String pattern, int patternIndex);


    @Override
    public boolean equals(Object other) {
        if (this == other) {
            return true;
        }
        if (!(other instanceof AbstractRegexpMethodPointcut)) {
            return false;
        }
        AbstractRegexpMethodPointcut otherPointcut = (AbstractRegexpMethodPointcut) other;
        return (Arrays.equals(this.patterns, otherPointcut.patterns) &&
                Arrays.equals(this.excludedPatterns, otherPointcut.excludedPatterns));
    }

    @Override
    public int hashCode() {
        int result = 27;
        for (String pattern : this.patterns) {
            result = 13 * result + pattern.hashCode();
        }
        for (String excludedPattern : this.excludedPatterns) {
            result = 13 * result + excludedPattern.hashCode();
        }
        return result;
    }

    @Override
    public String toString() {
        return getClass().getName() + ": patterns " + ObjectUtils.nullSafeToString(this.patterns) +
                ", excluded patterns " + ObjectUtils.nullSafeToString(this.excludedPatterns);
    }

}
